Heretofore, devices for dressing a grinding wheel have usually been mounted on a grinding machine to which the grinding wheel is brought for dressing the angle of the wheel. In some cases, the dressing tool is used as an attachment for the machine on which a cutter is being ground, but the difficulty has been to orient the path of travel of the dressing tool across the periphery of the grinding wheel and to obtain the correct shape for gullet forms on different shear angles. This is especially true where it is desired to obtain the same form from the first tooth to the last on the broach insert. In other instances, extensive mathematical computations and/or the use of templets in moving the tool through different selected curvilinear paths has been used in order to provide the curvature of a grinding wheel, or the like, to provide a true curvature to the workpiece, such as for example, when a form tool, such as a broach or the like, is ground there is provided a close tolerance uniformity between successive ground portions thereof, such as in the gullet from the first to the last tooth. Typical prior art apparatus and methods are illustrated in the following U.S. Pat. Nos. 1,686,802, 2,146,466, 2,178,135, 1,182,362, 2,158,423.
The invention of the present application has for an object the provision of an attachment device for a dressing, grinding or shaping machine. Preferably, the invention provides such device for a grinding machine, such as a broach grinder, which will produce uniformity from tooth-to-tooth and broach-to-broach, without removing the dresser from the machine. The invention provides a cam guide head and at least one adjustable slide. The cam head is swivelly mounted on the slide and locates the cam in an appropriate relationship to the wheel. The wheel is dressed by a tool which is carried in a holder, and the holder is adapted to be selectively moved back and forth along the cam to complete the dressing operation.
In the preferred form, the dressing device is mounted upon the frame or hub of the motor housing through which the grinding spindle extends. Thus, the dresser is always in position for dressing the wheel, and the operator can perform such dressing operation in any position, even while the machine is in motion. By this arrangement, increased operator output and reduction of wheel waste can be achieved without sacrifice in quality.
In the present invention, only one cam is required for all portions to be ground, such as gullet sizes. Proper setting of the diamond in the dressing unit automatically determines the size radius required for the desired pitch in the gullet to be ground. This arrangement is readily applied for gullet forms on different hook angles with minimum adjustment.